Autonumber Until Certain Value then Restart

option:

Sub test()

Dim lrow As Long, i As Long, j As Long

lrow = Cells(Rows.Count, 3).End(xlUp).Row
If lrow = 1 Then Exit Sub

result = Range("a1:a" & lrow)

For i = 2 To lrow
    j = j + 1
    If j > 5 Then j = 1
    result(i, 1) = j
Next

Range("a1:a" & lrow) = result

End Sub